ADDITIONS TO THE REVISED EDITION OF 1880. 739 



tism, but it is more apt to be accompanied by severe joint-disease 

 and suppuration. Besides these, there may be inflammations of 

 serous membranes, pleuritis, pericarditis, or meningitis, also pneu- 

 monia, etc. 



The prognosis is less favorable than in measles ; mild epidemics 

 are less frequent, and even mild cases often become complicated ; 

 this is justly called a treacherous disease. In not a few epidemics 

 the mortality will reach one-third. Cases in children under five 

 years or in old persons, those with high fever, intense and long-con- 

 tinued eruption, or with any of the severe complications, are unfa- 

 vorable. 



2. P. 607. 



Some persons are so susceptible to the poison that it acts even 

 when very dilute, as coming through the windows from the next 

 house, or by letters, paper money, etc. The nature of the poison ia 

 not understood. Minute spherical bodies (bacteria) have been found 

 in the contents of the pustule, in the skin around it, and in the in- 

 ternal organs ; . but it is not certain that these bacteria are the vehi- 

 cles of the contagion. The results of the experiments of Chauveau, 

 Jlur 'don- /Sanderson, and others, in removing the bacteria from vac- 

 cine lymph, do not agree with those of M. Wolff and Hillier. 



Weigert believes that the first changes, which occur in the cells of 

 the rete Malpighii, are not of inflammatory nature, but are analogous 

 to changes caused by diphtheritis in the epithelium. The cells of 

 the rete are transformed into translucent flakes of irregular shape 

 and size, and without nuclei ; they cause an irritation, which induces 

 an effusion of lymph that separates the affected cells, forming small 

 interspaces in a sort of mesh-work made by the remains of the epi- 

 dermis. About these interspaces there is active cell-proliferation, 

 and numerous pus-corpuscles escape from the vascular loops lying 

 under the swollen papillae of the skin, which gradually fill the meshes 

 as the efflorescence ripens. In regard to the central excavation in 

 many pocks, it is not a constant appearance, and is said by Rind- 

 fleisch to occur where the pustules develop around a hair-follicle or 

 sweat-gland, and to be caused by the covering of the pustule being 

 held down by the epidermis projecting into these depressions. 



On the mucous membranes variola is often accompanied by 

 catarrhal redness and swelling ; but where these membranes are 

 exposed to the air, there is a pustular eruption like that on the skin. 

 When patients die in the eruptive stage, the spleen is usually much 

 enlarged. 



When delirium occurs in small-pox, it may be due to the fever, 



